普洱茶中水溶性果胶的含量测定

[目的]探索适合普洱茶中水溶性果胶含量的测定方法。[方法]采用水提醇沉的提取方法,并用3,5-二甲基苯酚比色法测定普洱茶中水溶性果胶含量。[结果]试验表明,在波长448 nm处,3,5-二甲基苯酚比色法的线性方程是y=0.009 9x-0.004 4,R2=0.998 9,普洱生茶和熟茶的水溶性果胶回收率分别为96.6%、95.6%,RSD=2.89%、0.82%(n=6)。采用该方法测定的普洱茶生茶和熟茶水溶性果胶含量分别为1.89%、4.97%。[结论]3,5-二甲基苯酚比色法测定普洱茶中水溶性果胶方法简便、准确,回收率高,数据稳定,可作为普洱茶水溶性果胶含量的测定方法。

Study on the Determination of Water-soluble Pectin in Pu'er Tea

[Objective] To explore suitable method for the determination of the water-soluble pectin in Pu'er tea.[Method] Water-soluble pectin in Pu'er tea was extracted by water and alcohol precipitation and was determined by 3,5-dimethylphenol colorimetric method.[Result] The results show that at wavelength of 448 nm,linear equation was y = 0.009 9x-0.0044,R2 = 0.998 9,recovery rate were 96.6%,95.6%,RSD = 2.89%,0.82%(n = 6).By this method,respectively water-soluble pectin content is 1.89%,4.97% in Pu'er tea raw tea and ripe tea.[Conclusion] The method is simple,accurate with high recovery rate and stable data,which can be used as the method for determination of water-soluble pectin content in Pu'er tea.